The invention relates to a method of manufacturing a ceramic multilayer component, comprising electrically conductive and electrically insulating layers which are stacked in alternate arrangement in a multilayer structure. Examples of such components include ceramic multilayer capacitors, actuators and transformers.
A method as stated above is known, for example, from European Patent Application EP-A 0 777 913. In the method therein described, a multilayer component is manufactured using sheets of green ceramic tape (each sheet being a dried slurry of ceramic particles in an organic binder). Each sheet has a thickness of the order of about 10 .mu.m, and lateral dimensions of the order of 100.times.100 mm.sup.2. Using a screen printing technique, each sheet is provided on one major surface with a matrix of planar metallic electrodes (comprising silver-palladium ink, for example, in a film having a thickness of the order of 1 .mu.m). Many such sheets are arranged on top of one another in a multilayer stack, in such a manner that the electrodes are staggered back and forth in alternate layers. This stack is then compressed into a laminated sheet which is subsequently cut into strips, each strip comprising a linear array of electrode stacks, the cutting lines defining the strips being thus chosen that, along each long side wall of each strip, only alternate electrodes are exposed. After sintering these strips, their side walls can be provided with electrical contacts.
This known method has a number of disadvantages. For one, the layers of ceramic tape are relatively thick (because they must be self-supporting); as a result, because the total (cumulative) thickness of the finished component generally must fall within standard tolerances, the number of layers in the component is substantially limited (typically to a maximum of the order of about 150). In the case of a ceramic multilayer capacitor, this limitation restricts the achievable capacitance, which is quadratically proportional to the number of layers in the stack. In addition, the time required to manufacture a stack of n layers increases substantially linearly with n; increasing n by a factor p therefore requires the use of p times as many stacking machines, if a given manufacturing output is to be maintained. Another disadvantage is that, because relatively large areas of each ceramic sheet are not covered by electrodes, whereas other areas are covered, cumulative thickness-discrepancies arise as more and more layers are stacked, and such discrepancies can cause the stack to distort. Moreover, the extent to which the electrodes in alternate sheets are staggered back and forth is typically about 50% of the width of each electrode, which means that only a relatively small portion of each electrode contributes effective area to the finished component, leading to considerable waste.